Long term magnetic review and forecast
27 day forecast of magnetic activity for the polar cap, auroral zone and sub-auroral zone.
Review of magnetic activity in the polar cap, auroral zone and sub-auroral zone for the last 31 days.
|Polar Cap||0 - 40||40 - 100||100 - 160||160+|
|Auroral Zone||0 - 60||60 - 160||160 - 240||240+|
|Sub-Auroral Zone||0 - 20||20 - 40||40 - 80||80+|
For each of the three major zones (subauroral, auroral, polar cap), the range of activity is divided into four classifications: quiet, unsettled, active, storm. The actual parameter used for reporting and forecasting magnetic activity is a daily index. It is known as DRX and is the average of the hourly ranges (maximum minus minimum during each hour) in the X (northward) component of the magnetic field intensity for a day (the UT or GMT day), ie DRX for the zone is the mean of 24 values. Because this averaging process has the effect of smoothing (filtering) the more rapid fluctuations in the field, the qualitative descriptors are defined rather differently than for the short-term forecasts. Units are nanoteslas (nT).